1. Field of the Invention
The invention concerns a device for bearing and driving a part, tiltable on a tilt axis, of a gantry of a computed tomography apparatus—which gantry has the tilt axis—relative to a pedestal of the gantry of the computed tomography apparatus. The invention also concerns a computed tomography apparatus that embodies such a device.
2. Description of the Prior Art
Computed tomography apparatuses of the third generation have a gantry with a stationary part and a part that can be rotated relative to the stationary part, around a system axis of the gantry. The rotatable part has the shape of a drum on which are arranged the components of the computed tomography apparatus (such as the x-ray source, the x-ray detector, a control system, etc.) that rotate around a patient arranged along the system axis in a measurement field during operation of the computed tomography apparatus. Given a system with only one x-ray source and one x-ray detector, a completely populated drum reaches a mass of approximately 800 kg to 900 kg and rotates with a rotation speed of up to 240 R/min during operation.
For specific examinations it is necessary to tilt or pivot the x-ray system around a tilt axis that is at a right angle to the system axis, the tilt angle essentially proceeding horizontally. The tilt angle amounts to at most +/−30° out of the starting position. The rotatable part and the stationary part of the gantry are normally tilted relative to a pedestal of the gantry. The tilting must be able to occur exactly, precise to a minute of a degree. Presently, roller bearings or slide bearing bushings are used to support the stationary and rotatable part relative to the pedestal of the gantry. Such roller bearings or slide bearing bushings are subject to a certain wear and must be regularly serviced (re-oiled, for example). For example, the drive comprises a motor interacting with a worm gear.